Minolta md lens aperture stuck?

[Nhyrum]

I recently got my first camera, a Minolta x 700. After about half a roll of film, I realized that the preview button did nothing, regardless of being in program or aperture modes, and regardless of the aperture set. I took the lens off and made sure the arm that's moved by the button moved freely, and the lever on the lens moves freely as well, but even manually moving the arm on the lens and changing the aperture ring, I don't see anything physically happening looking through either end of the lens. I assume I should see the size of the aperture close as the f number gets higher? With the cost of these lenses, I assume a repair isn't quite worth it? After I get a different lens, would it be worth trying to take apart the lens to see what's stuck inside? Would I even be able to get that deep in the lens? At that point, I'd basically count the lens as garbage, and if I get it working, great! I've got a limited amount of optic knowledge, I was a Canon trained service technician for their printers and copy machines, and some of the older machines still has optical scan beds.

 

[cgw]

The aperture, of course, will not change off camera unless the stop down lever is moved. That's what the camera does just before the shutter opens and closes. That's why the VF stays bright regardless of set aperture. Sounds like the body's stop down linkage is wonky. Beginning to wonder from previous posts whether you're the owner of a duff X700?

 

[Nhyrum]

I've manually moved the stop lever on the lens and nothing happens, regardless of where the ring is set. The mechanism on the camera works fine.

 

[cgw]

Then I'd guess junk lens. Any chance the return spring on the stop down lever is disconnected or missing?

 

[wfooshee]

I would bet that the leaves of the aperture move by spring pressure and not a positive actual mechanical link forcing them to move. Basically, the lever retains the aperture at full open, and when the lever is moved, the leaves are free to close, driven by spring pressure.

If they're stuck, they don't move. If the spring is broken, they don't move. Any number of things could cause them to be stuck, from a single blade being bent, to congealed oil or some other contaminant.